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Does B12 Really Give You an Energy Boost?

If you’re deficient, getting more B12 can recharge your battery.

30-Second Takeaway

  • Vitamin B12 is essential for energy. If you don’t get enough of it, you can feel fatigued, weak, and generally run down.
  • Eating B12-rich foods, oral supplements, and B12 injections can all raise your levels back to the normal range.

Plenty of supplements claim to boost energy and fight fatigue. Few deliver. One that actually might: vitamin B12.

Low levels of the nutrient are linked with fatigue—so much so that some people with a B12 deficiency report feeling like they’re dying. And some who supplement with it say they feel “born again.” Sounds pretty promising. But does vitamin B12 give you energy regardless of the cause?

That’s worth a closer look. 

What Is B12?

Also known as cobalamin, vitamin B12’s biggest claim to fame is its role in blood cell formation and nervous system function.

But B12 isn’t a one-trick nutrient: It also helps with DNA synthesis and the formation of brain and nerve cells (1).

Does Vitamin B12 Boost Energy Levels?

There’s a direct link between vitamin B12 and energy.

B12 helps your body convert fat and protein to provide energy to your body, says Peter Kozlowski, M.D., a functional medicine doctor in Chicago.

Your body also needs B12 to make red blood cells, which ferry oxygen to your tissues, a process that’s needed to feel strong and energized throughout the day.

B12 is also vital for your nervous system. It maintains myelin–a fatty nerve insulator that optimizes signaling from your brain–to make sure muscles contract when they’re needed (among other things).

If your vitamin B12 levels are low (a blood test can determine if your levels are in the right range).

A B12 deficiency can cause a myriad of symptoms that zap your physical and mental energy. Getting those levels back up through supplementing typically helps improve symptoms, says Kozlowski.

Anecdotally, people who have enough vitamin B12 report feeling hyped-up after B12 injections. Some doctors are starting to listen: In one Swiss study (2), almost half of all general practitioners agreed with prescribing B12 for unexplained fatigue.

Vitamin B12 at a Glance

  • Your body needs vitamin B12 to create red blood cells and DNA. Your nervous system also uses it to maintain myelin.
  • If you are B12 deficient, you may feel fatigued, weak, and depressed. Supplementing with B12 often erases these symptoms.
  • Some people who aren’t B12 deficient also feel energized after supplementing with the nutrient.

Vitamin B12

Signs of B12 Deficiency

About six percent of Americans under the age of 60—and 20 percent of those over 60—have a B12 deficiency (1). Not getting enough B12 doesn’t just make you feel devoid of energy; it can make you downright miserable. Here’s just a few symptoms you might spot:

Since your body stores a lot of B12, a deficiency doesn’t happen overnight—it can take years to show up and cause these symptoms (3).

Causes of B12 Deficiency

Most people get enough B12 from their diet (3), but dig deeper and you’ll discover that you can chow down on enough B12-rich food and still be deficient. How’s that work?

Some acid-blocking medications, such as PPIs (omeprazole, lansoprazole)—which are among the most-prescribed drugs in the U.S. (4)—can interfere with B12 absorption. The same goes for certain antacids (cimetidine), and the diabetes drug metformin.

Mental and emotional factors like stress, anxiety, and depression can also affect the release of stomach acid needed to digest protein (which ensures that B12 is released from your food), says Kozlowski.

Other people who might not get enough from their diet? Vegetarians and vegans, since the nutrient is mainly found in meat and dairy.

Medical conditions that can also put you at risk for a B12 deficiency include:

Vitamin B12, now available from Hone, may boost your energy, reduce stress, and support your brain. Connect with a doctor to see if it’s right for you. 

How Does B12 Work?

B12 is bound to protein in meats and animal products (5). As these foods travel through your digestive system, your stomach releases hydrochloric acid and enzymes which set the B12 free. 

The unbound B12 then combines with another protein (called intrinsic factor, which is secreted by cells in the stomach) before it is absorbed by the body in the small intestine and put to work.

If you’re taking a supplement or eating fortified foods (such as breakfast cereal), your body can skip the first step of breaking B12 off from the protein, making absorption easier.

B12 is a water-soluble vitamin, so any excess B12 intake will be peed out.

Vitamin B12 in Your Diet

The National Institutes of Health recommends that the average man consume a mere 2.4 micrograms a day, which you can get by scarfing just three ounces of ground beef. Other B12-rich food options include:

B12 in Your Body

  • Your body can’t make B12. You need to get it from food or supplements.
  • When you eat B12-rich foods, your body releases enzymes that release it so your body can use it.
  • Most dietary B12 come from animal sources. Cereals, nutritional yeast, and some dairy products are also often fortified with B12.


Get More B12

If a blood test determines that you’re clinically deficient (that’s lower than 200 picograms per milliliter (pg/mL)—or if you just want to see if B12 can put more tiger in your tank—you can up your levels a few ways.


If you’re a meat-eater, leveling up your B12 could be as simple as making sure that you’re eating enough B12-rich foods every day, according to the Cleveland Clinic. (6)

Oral Supplements

Vegetarians, vegans, and people who suffer from medical conditions that makes it hard for the gut to absorb nutrients may need a supplement to boost their B12 levels and energy.

You can find B12 on its own, or in a dietary supplement with other B vitamins and other nutrients. Supplements with a variety of B vitamins in them will have less B12 than a standalone B12 pill.

B12 deficiency often goes hand in hand with a folate deficiency, says Kozlowski. For that reason, your doctor may order a serum folate level when testing for B12. “Both vitamins are needed for DNA synthesis and your body will not function properly if both levels are not balanced,” he says. (Normal serum folate levels are above 3 ng/mL.) (7) If you’re low in both, B-complex vitamin might help. Talk to your doctor about the dose that’s right for you.

Vitamin B12 Injections

In instances where someone has lower levels of the nutrient, B12 injections can bring levels up faster, says Kozlowski. 

B12 can be injected underneath the skin or into the muscle. You can get your B12 shot in a doctor’s office, but your doctor may also give you the okay to self-inject at home.

You can work with Hone to see if B12 injections are right for you. Simply create an account, then describe your symptoms using Hone’s online form. A board-certified physician will review your answers, and prescribe B12 shots if appropriate.

The Bottom Line

If you don’t get enough B12, you can suffer symptoms like muscle weakness, fatigue, memory problems, dizziness, short breath, and heart palpitations. If a blood test confirms that your B12 levels are low, supplementing can get your levels of the nutrient back to normal and help you feel more energized. If your B12 levels are normal, there is no evidence that supplements will further boost your energy.